<jats:title>Abstract</jats:title><jats:p>The investigation of the MeOH extract of the leaves of <jats:italic>Chisocheton weinlandii</jats:italic> H<jats:sc>arms</jats:sc> (Meliaceae) revealed two new open‐chain spermidine alkaloids, chisitine 1 (<jats:bold>1</jats:bold>) and chisitine 2 (<jats:bold>2</jats:bold>). Their structures were elucidated by NMR spectroscopy, tandem‐mass spectrometry, and independant syntheses (<jats:italic>Scheme 3</jats:italic>). Detailed MS/MS fragmentation pathways are discussed for both compounds based on H/D exchange and <jats:sup>18</jats:sup>O‐labeling experiments (<jats:italic>Schemes 1</jats:italic> and <jats:italic>2</jats:italic>).